Typical manufacturing duties in an automated manufacturing environment include translating or rotating a piece for assembly, cutting, wire bonding, or some other necessary process. Many manufacturing applications currently utilize either physical positioning of the piece or object requiring human interaction, or some type of pick-and-place device or robot manipulation device. Other manufacturing applications use a mechanical evaluation setup, or transportation devices, to verify orientation of an object before the object is passed to a subsequent location.
For micro-device applications and some larger industrial applications, human interface and evaluation is commonly employed to verify correct orientation of the work piece. Human interface requires time and effort on the part of an operator which could be directed elsewhere.
Currently, chips used in microdevices, such as multi-chip modules (MCMs), opto-electronic integrated circuits (OEICs) and implantable medical devices, can generally be loaded in a particular orientation. These objects are then placed in the correct location by pick-and-place machines. Some micro-device applications use special automatic orienting and feeding mechanisms to align the pieces for the necessary task. These orienting and feeding mechanisms properly orient the target piece for only a single task, and improper orientation which occasionally occurs can cause problems.
Physical positioning mechanisms, or "pick-and-place" devices simply repeat the same task over and over. If a piece is incorrectly sized or positioned, the pick-and-place mechanism will not operate properly. Hence, pick-and-place devices usually require additional apparatus to ensure that the work piece is the proper size, in the proper orientation, and in the proper orientation before the pick-and place mechanism performs the requisite function.
Robots may or may not have sensory feedback capability, and a robot without sensory capability is essentially the same as a pick-and-place device. Robots having sensors can detect improper sizing, orientation, or placement, but require expensive programs for proper application and reprogramming when the application is changed. Further, robots are large devices relative to the part which require intricate control capability, and they may damage delicate pieces, such as micro-devices or microcircuits. Automation notwithstanding, the necessity for human supervision makes these systems relatively costly and operator intensive.
Other automated positioning systems use feeder bowls or other special arrangements, such as "chutes" to filter parts through a passageway, or obstructions mounted on the side of translation paths to correct the position or orientation of the target part. These devices are relatively simple, may occasionally produce errant results, and cannot be easily changed if the necessary task changes.
Larger applications of orientation and manipulation of objects is illustrated in limited translational devices using air currents, and combined translational and rotational devices again using air as the force modality. Several air current translation and rotation devices use a position evaluating device, such as a light beam, to determine when the object has attained a desired position or orientation.
Airflow prior art may be illustrated by example. U.S. Pat. No. 3,279,863 to Bouladon, et al., illustrates an air layer transporter, resembling the common "air hockey" game played by children. No variable control over the direction of the flow of air is provided. The airflow, position and transportation direction of the object are essentially fixed. The system has four different types of valves providing force in different directions, but the orientation of air flow is fixed so as to move the object in a single direction over the surface. Universal control is unavailable, only specific, predetermined control of the direction of the object.
Various schemes involving light, back pressure, vision, etc. are available to control the stopping and starting of the sequence of such air-based surfaces. Judge et al., U.S. Pat. No. 4,618,292, presents one such example. Judge et al. illustrates a controlled positioning system which requires an electro-optic sensing device for proper operation. Judge shows a wafer having a specific shape, a circle with a notch cut therein, and provides a system for centering and orienting the wafer using a position sensing device, namely an electro-optic control arm. In order to work properly, the system requires the object to be in the shape of a notched circular wafer, and could not work with, for example, triangular or square pieces. Further, the system only provides orientation and positioning capability, not translational capability.
The need has arisen for manipulation, including translation and rotation of small pieces such as microdevices, within an automated manufacturing environment which allows proper orientation of the small piece. Many applications may vary depending on the piece manufactured or the process undertaken, so alteration of the controlled path of the system, not shown in the prior art, would greatly enhance system capability. For example, if a part for a system must be rotated for orientation in a particular direction, then passed to a subsequent location, the ability to alter the surface to perform some new function, such as moving the object to a new location in a different orientation, would be beneficial if the user desires to alter the procedure used at the subsequent location, i.e. if the device is to act as a programmable feeder and orienting device.
The size of the object dictates the means of transporting the object across the surface. Thus, a controllable motion surface should be operable for small as well as large objects, ranging from microns to meters, wherein the objects are of various shapes and the technology to transfer the object varies to suit the part and the application.
Accordingly, it is a principal object of this invention to develop a system which provides controllability over the position of an object on a surface. The invention must control a part presented in random orientation and translate and orient the part to a desired location, and provide flexible control able to change tasks relatively instantaneously.